Peel and section the fruit into a bowl, squeezing out all of the juice. Measure out 3/4 cup/175 ml of juice and put it in a saucepan with the wine. Add the sugar and heat to dissolve. Pour 1/4 cup/60 ml of the liquid into a bowl and soften the gelatin for a minute. Return it to the pan. Stir to dissolve, and boil 2 minutes. Cool completely.
Line a 1 quart/1 liter terrine or glass loaf pan with plastic wrap, leaving enough overhang to cover the terrine afterwards. Arrange the fruit sections decoratively in the terrine. Pour the liquid over. Chill the terrine, covered, until firm, at least 4 hours and up to 2 days. Garnish with mint sprigs or candied orange zest.